Over the last several weeks we dealt with the impact of a few hurricanes from H to K, i.e. Harvey, Irma, Jose, and Katia. Now that the Atlantic basin has quieted a wee bit, it is time we get back to the lighter side of things.
So we turn to xkcd and its look at ensemble models, often used to try and predict the paths of hurricanes.
Like many Americans I followed the story of Hurricane Irma over the weekend. One of my favourite pieces of reporting was this article from the Washington Post. It did a really nice job of visually comparing Irma to some recent and more historic storms, such as 1992’s Hurricane Andrew.
It can be difficult to truly compare hurricanes, sometimes they are small and compact, other times more dispersed. Irma was just big with lots of potentially destructive power spread out across a wide area, almost the width of the Floridian peninsula. The article uses several graphics—I am also quite partial to the satellite image comparison so check out the article—but this one is perhaps my favourite.
It uses a colour palette that deepens in redness nearer the storm’s centre. This allows the user to compare the geographic area or footprint of the storms destructive winds.
I wonder, however, what would happen if the designers had superimposed each graphic atop the other. It might have allowed for an even better comparison of size instead of having to have the user mentally transpose each hurricane.
Still, a really nice graphic and visual article.
Credit for the piece goes to Bonnie Berkowitz, Laris Karklis, Reuben Fischer-Baum, and Chiqui Esteban.
Your author is on holiday today and is actually writing today’s post on a Thursday night train to Boston. But by the time he returns late Sunday night—a Monday morning post is not guaranteed—Hurricane Irma will have likely made landfall somewhere along the Florida coast.
Thursday the Guardian published a nice article looking at the potential tracks for Irma. And while the specific routes will certainly be amended and updated over the weekend, the article is worth looking at prior to Irma’s arrival at Florida. As of my writing the track has shifted ever slightly westward and the current predicted path looks for Irma to land south and west of Miami. Ergo this screenshot is already a little outdated.
The remarkable thing about this graphic, which is just a cleaner version of the standard meteorological maps through more a more considered palette, is that there is not just one path of winds, but three. Following quickly on the heels of Irma are Katia and Jose, the latter the one taking the nearly same path as Irma while Katia spins towards Mexico.
But the graphic I really wanted to look at is the one ending the piece.
This looks at the countries in Irma’s path as of Thursday morning. What I do not understand is the vertical axis of the bars. What does the height represent? To simply show the rank of countries able to cope with natural disasters, a more straight-forward table could have been used. A dot plot would also make some sense, but again, it would require an understanding of the underlying metrics driving the chart.
The graphic is saved by the annotations, in particular the more/less vulnerable directional arrows. Because I do not understand why countries are grouped into the particular buckets, I find the coloured bins out of place.
I think the concept of showing the most vulnerable countries is terribly important, however, the graphic itself needed a little more thought to be a little more clear in presenting the concept.
Credit for the piece goes to the Guardian graphics department.
Irma swept the northern coast of Puerto Rico last night after devastating some of the Leeward Islands. What’s next? Well after the Turks and Caicos, Cuba, and the Bahamas we are probably looking at a Florida landfall. (Though in the last 24 hours the track has shifted ever eastward so Tampa Bay looks fine from a direct impact standpoint.)
Harvey was an exception in many ways because most deaths occur not from rainfall flooding, but from the storm surge. Basically a massive wave of water driven by low pressure and strong winds that is literally pushed ashore.
Now even though I just said that, I wanted to talk about the winds for a second. Why? Well it turns out that at 185mph, Irma has some of the strongest sustained winds ever recorded for an Atlantic hurricane. And 185mph winds, they can do quite a bit of damage. How much? Well for that we turn to this illustration from Vox.
Assuming the worst case scenario and Irma would strike just southwest of Miami, say Homestead or Key Largo, 185mph winds could do some damage to non-hurricane-safe buildings in a very large American city. And then there is the storm surge, which could be problematic for a city that is already struggling with rising tides. (Thanks, climate change.) The reason I say worst case is southwest of Miami is because hurricanes do most of the their damage—though certainly far from all of it—on their righthand side, which in a northward moving storm would be the eastern half.
The rest of the Vox piece does a nice job explaining Irma, its historic nature, and how it could be so dangerous. Worth a quick read, unless you live in Florida and then you should probably be packing up to evacuate.
Let’s consider today a follow-up to yesterday’s piece. (No, I do not believe I have ever done a follow-up piece, but why not start now all these years later.)
Yesterday we looked at the Post, Journal, and Times for their coverage of the fallen rain amounts in southeast Texas. But at the time, we only had actual totals from the Post and Journal. The Times had only produced a projection map. The Times piece yesterday was perhaps the most underwhelming of the three, though it certainly did some things correctly, namely it was small, simple, and quick to get the reader to the point that Houston was likely to be flooded by storm’s end.
What is different about this piece? Well this one is an animated .gif showing the cumulative rainfall. In other words, Texas starts dry and every hour just makes the map bluer and bluer. An additional feature that I find particularly useful is the dot map, which indicates where the heaviest rain was falling in each hour. Especially early on in the event, you can see the bands of rain sweeping in from the Gulf.
The bins also work better here, though I wonder if more segregation or a different palette would have worked a bit better. But, my biggest critique is the same I have with many animated .gifs: the looping. And unfortunately I do not have an easy solution. You certainly need to see it loop through more than once to understand the totality of the rainfall. But then I really do want to be able to examine the final map, or at least final as of 03.00 today.
Anyway, this was a really nice piece that should have been showcased alongside the others yesterday.
Credit for the piece goes to Gregor Aisch, Sarah Almukhtar, Jerey Ashkenas, Matthew Bloch, Joe Burgess, Audrey Carlsen, Ford Fessenden, Troy Griggs, K.K. Rebecca Lai, Jasmine C. Lee, Jugal K. Patel, Adam Pearce, Bedel Saget, Anjali Singhvi, Joe Ward, and Josh Williams.
Hurricane Harvey landed north of Corpus Christi, Texas late Friday night. By Monday morning, Houston has been flooded as nearly two feet of water have fallen upon the city, built on and around wetlands long ago paved over with concrete. Naturally the news has covered this story in depth all weekend. Even leading up to it, when I was still posting eclipse things, various outlets had projections and why we should care graphics. But as the storm begins to move back into the Gulf—only to move back inland tomorrow—I wanted to compare some of the graphics I have been seeing.
Of course, not all graphics are the same, let alone cover the same things. So this morning we are looking at just the rainfall total maps of a few different outlets.
From the Washington Post, we have the following graphic.
The palette chosen performs well at quickly scaling up to the record level of rainfall, i.e. the 20+ inches realm, but quickly shifting from the green–blue palette into dark purples.
Here we have a more familiar blue–red diverging spectrum. The point of divergence set to 20 inches.
Lastly, we have the New York Times graphic. Though in this case, it’s not an exact like-for-like comparison. I could not find a graphic mapping total rainfall, instead this is for projected rainfall totals. But the design is for the same type of map, i.e. how much rain falls in a location.
The Post takes the closest approach to the true continuous spectrum palette, where the shift from dry to drenched is gradual. It makes for a smoother, more blended looking map. Somewhere around that 20 inch point, however, the palette shifts from the green to blue range to purple. It emphasises the record-hitting point, but otherwise the totals are presented as more fluid. Perhaps correctly since rain does not neatly fall evenly into pixels.
By comparison, the Journal segments the rainfall totals into bins of blues. The scale is not even, the lighter blues incorporate two inches, the darkers upwards of five. And then again, like the Post, separate 20+ as a different colour, here switching to reds.
Lastly the Times keeps to a simple segmented bin palette of all blues. 20+ inches is rendered is just a dark blue.
Each map has pluses, each has minuses. The Times map, for example, is simple and quick to understand. Southeastern Texas will be wet by the middle of next week. If your goal is only to communicate that point, well this map has done its job. It is worth noting, again, that this is a map of projections. Because the other thing missing from this map is the storm’s path. So if the goal were to showcase the rainfall along the storm’s path, well this graphic does not accomplish that nearly as well as the other two.
The Post and the Journal both show the track of the storm. The Journal takes it one step further and plots its projected course through Thursday. This helps us really see if not understand the east side problem of hurricanes. That is, the eastern quadrants of hurricanes typically experience the heaviest amounts of rain. And as the darker portions of the map all fall to the north and east of those lines, it reaffirms this for us.
So what really differentiates the two? The colour palette and its application. The Post’s palette is more natural as, again, rain does not fall neatly into bins and instead makes for blurred and messy totals across a map. Separating the heaviest rains into the purples, however, makes a lot of sense as that amount of rainfall, as we are seeing this morning, makes for a mess in Houston.
But the point of a graphic is to translate nature and the observed into a digestible and pointed statement of the observed. What should I learn? Why should I care? The Journal, like the Post, does a fantastic job of splitting out the 20+ inch totals by using a divergent palette. But instead of blending into that colour, the distinction is sharp. And then below that threshold, we get rainfall totals segmented into just a few bins. These help the reader see, also more starkly because of the selection of the specific blues, just where the bands of heavy rain will fall.
I do want to point out, however, that all of these maps occur in articles with lots of other fantastic graphics that visually explore lots of details about the story. And in particular, I want to highlight that the normal bit where I state the credits includes a lot of people. Creating a whole host of graphics to support a story takes a lot of work.
Credit for the Washington Post piece goes to Darla Cameron, Samuel Granados, Chris Alcantara, and Gabriel Florit.
Credit for the Wall Street Journal piece goes to Bradley Olson, Arian Campo-Flores, Miguel Bustillo, Dan Frosch, Erin Ailworth, Christopher M. Matthews, and Russell Gold.
Credit for the New York Times piece goes to Gregor Aisch, Sarah Almukhtar, Jeremy Ashkenas, Matthew Bloch, Joe Burgess, Audrey Carlsen, Ford Fessenden, Troy Griggs, K.K. Rebecca Lai, Jasmine C. Lee, Jugal K. Patel, Adam Pearce, Bedel Saget, Anjali Singhvi, Joe Ward, and Josh Williams.
We made it to Friday, folks. So here in Philly it is, of course, hot and disgusting. (Please refer to Tuesday’s post about the increasingly hot weather in summers.) Thankfully we have ThisIsIndexed to explain what happens in hot weather.
Today, 9 February, it finally snowed significantly here in Philadelphia. In Chicago it probably snowed shortly after I moved out in September. Today’s graphic is a forecast map from philly.com using National Weather Service (NWS) data.
I fail to understand the divergent palette—to be fair this is not the only instance of it throughout the meteorological world. There is a split at the six-inch mark—but why? If anything, my eye would think that the 4–6 range is the heaviest, not the yellow. Snowfall is usually more of a continuous range, and so both within the blues and yellows you get that through a softer edge as the colours become more intense. And then you hit the six-inch mark and a violent shift.
I am also curious as to why the choice to use a coloured map background. Especially if the colour, a lightish green-blue is so close to the lightish blue used by the map to forecast snowfall.
In short, I think this Philadelphia map could use some attention from some designers to make the message a bit clearer.
Credit for the piece goes to the philly.com graphics department.
In moving back to Philadelphia from Chicago, I have forsaken polar vortices for hurricanes and nor’easters. And this current weekend, it appears increasingly likely that the weather will be impacted by Hurricane Matthew, presently tearing its way through the Caribbean. So of course I am following projections and forecasts of just where this storm will be headed.
Thankfully Mashable has an article that attempts to explain just what the National Hurricane Center (NHC) means when it publishes its cone of uncertainty charts. Because, according to the article, it turns out most people do not entirely understand just what it means.
Credit for the piece goes to the National Hurricane Center.
One of the things I like about Chicago’s WGN network is its weather blog. They often include infographic-like content to explain weather trends or stories. But as someone working in the same field of data visualisation and information design, I sometimes find myself truly confused. That happened with this piece last Friday.
The map in the upper-right in particular caught my attention and not in the good way. The overall piece discusses the heavy rainfall in the Chicago area on Thursday and the map looks at the percentage increase in extreme weather rainfall precipitation. All so far so good. But then I look at the map itself. I see blue and thing blue > water > rainfall. The darker/more the blue, the greater the increase. But, no—check out Hawaii. So blue means less rainfall. But also no, look at the Midwest and Southeast. So does green mean anything? Beyond being all positive growth, not that I can tell. As best I can tell, the colour means nothing in terms of rainfall data, but instead delineates the regions of the United States—noting of course they are not the standard US Census Bureau regions.
So here is my quick stab at trying to create a map that explains the percentage growth. I have included a version with and without state borders to help readers distinguish between states and regions.
And what is that at the bottom? A bar chart of course. After all, with only eight regions, is a map truly necessary especially when shown at such an aggregate level? You can make the argument that the extreme rainfall has, broadly speaking, benefitted the eastern half of the United States. But, personally speaking, I would prefer a map for a more granular set of data at the state or municipality level.
Credit for the piece goes to Jennifer Kohnke and Drew Narsutis.